An extreme version of vorticity is a vortex. The vortex is a spinning, cyclonic mass of fluid, which can be observed in the rotation of water going down a drain, as well as in smoke rings, tornados and hurricanes.

A sell-out crowd of 10,000 then observed perfectly a period of silence before the team revealed their black armbands, complete with stitched-in poppies, for the match. After Fifa’s about-turn, it must have been a frantic few days for the England kit manufacturer. The on-field challenge was altogether more straightforward.

Elbows almost touching they leaned at ease, idly reading the almost obliterated lines engraved there. ¶ "I never understood it," she observed, lightly scornful. "What occult meaning has a sun-dial for the spooney? I'm sure I don't want to read riddles in a strange gentleman's optics."